bookcart.java

一个用Jsp+javaBean+sevlet写的购物车

/*
 * Created on 2006-12-11
 *
 * TODO To change the template for this generated file go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
package Book03;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author jzxy
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */

import java.io.PrintWriter;
import javax.servlet.http.*;
import java.sql.*;
import java.util.*;
import JavaBean.Book;
import JavaBean.DbMysql;
/**
 * @author Administrator
 *
 * TODO 要更改此生成的类型注释的模板，请转至
 * 窗口 － 首选项 － Java － 代码样式 － 代码模板
 */
public class BookCart extends HttpServlet {

	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		//TODO Method stub generated by Lomboz
		Book book=null;
		HttpSession session=request.getSession(true);
		Vector booklist=(Vector)session.getAttribute("bookcart");
		PrintWriter pw=response.getWriter();
		
		//如果结帐
		if(request.getParameter("count")!=null){
			float totalcost=0;
			for(int i=0;i<booklist.size();i++){
				Book buybook;
				buybook=(Book)booklist.elementAt(i);
				if(buybook.getName()!=null){
					totalcost+=(buybook.getPrice()*buybook.getNum());
				}
			}
			session.setAttribute("totalcost",Float.toString(totalcost));
			response.sendRedirect("Check.jsp");
		}
		
		//如果加入购物车
		if(request.getParameter("ID")!=null){
			DbMysql db=new DbMysql();
			ResultSet rs=null;
			String booknum=request.getParameter("num");
			String ID=request.getParameter("ID");
			String str="select * from book where ID='"+ID+"'";
			try{
				rs=db.executeQuery(str);	
				while(rs.next()){
					book=new Book();
					book.setName(rs.getString("name"));
					book.setAuthor(rs.getString("author"));
					book.setPublisher(rs.getString("publisher"));
					book.setPrice(rs.getFloat("price"));
					book.setNum(Integer.parseInt(booknum));
				}
			}
			catch(Exception se){
				System.err.println(se.getMessage());
			}
			
			//判断购物车如果为空就直接添加一个新的book对象进Vecotr向量booklist
			if(booklist==null){
				booklist=new Vector();
				booklist.addElement(book);
			}
			//如果不为空
			else{	
				//判断有没有某一本书的记录,有的话更改book对象的num属性
				boolean bo=false;
				for(int i=0;i<booklist.size();i++){
					Book bk=(Book)booklist.elementAt(i);
					if(bk.getName().equals(book.getName())){
						bk.setNum(book.getNum()+bk.getNum());
						booklist.setElementAt(bk,i);
						bo=true;
					}	
				}
				//没有的话添加一个一个新的book对象进Vecotr向量booklist
				if(bo==false){	
					booklist.addElement(book);
				}
			}
			session.setAttribute("bookcart",booklist);
			response.sendRedirect("BookCart.jsp");
		}
		
		//执行从购物车中删除
		else if(request.getParameter("delbook")!=null){
			String delbook=request.getParameter("delbook");
			booklist.removeElementAt(Integer.parseInt(delbook));
			session.setAttribute("bookcart",booklist);
			response.sendRedirect("BookCart.jsp");
		}
	}
	
	protected void doPost(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		//TODO Method stub generated by Lomboz
		doGet(request,response);
	}
}